Sorry, DD distracted me there.
I like lots of nibbly things for Christmas, both sweet and savoury. So crackers and cheese, pate, cured meats, cooked seafood (smoked salmon, cooked prawns etc), cherry tomatoes, pickles, ....and various types of crisps, mince pies, things with chocolate, naice biscuits, and some fresh fruit. Part baked bread is handy if there are no shops near or you can't be sure they'd be open (and easy to bring back and use at home if you find a lovely local bakery that would be better!).
I also like to have proper ground coffee from the cafetiere for leisurely breakfasts, and we have a metal cafetiere that is relatively bombproof that we bring away with us. And a lovely marmalade/jam for those leisurely starts.
A good book each, and maybe a local guidebook.
Warm clothes in layers, house may be cosy or freezing - and also something to wear on your feet indoors (slipper socks, cosy thick hiking socks, actual slippers etc) if not wearing shoes.
And also drinks - not just alcohol but mixers, soft drinks (we often bring a lot of fizzy water and nice cordials to mix), favourite hot drinks etc. And perhaps, if you like a snifter, a dash of brandy for French coffee or into grown up hot choc, etc. Cream for hot chocs and posh coffees and over mince pies.
A pack (or 2) of ready rolled all-butter puff pastry and a pack of good sausage meat (along with a good handful of cooking apple grated into the meat - lush!) means you can knock up some sausage rolls very quickly and easily.
I always want the makings of a full fry - we might do a full fry, or bacon butties, or sausage sandwiches, or use parts to make a pasta dinner some night we want a lighter meal...so very useful. And eggs have so many uses too! And cheese - regular cheese for cooking, (eg a bag of decent grated cheddar or emmentaul or mozarella to sprinkle into omlettes or over a toastie or on top of tomato soup) quite apart from the makings of a cheeseboard.
People have already said the emergency loo roll and kitchen towel - I add a pot scrubber to the shopping list, and have a washup brush in my box, and usually also bring at least 1 good cloth and a bottle of spray cleaner from home if I am driving - just in case there is a need for it and its' not there (lots of places are very poor on cleaning materials). And a spare hand towel and handful of teatowels too for the kitchen.
I normally also bring a hairdryer as it is vital to me and often not supplied - but I have a travel sized one anyway.
But then I get myself a lovely luxury shower gel (or bath bubbles if there's a bath) for the few peaceful moments I get there too.
Sorry, I know that's all a bit scattered, but hopefully its' helpful.